Research on drug abuse and addiction requires multi-disciplinary approaches. The Biochemical Pharmacology Core provides services for researchers who do not perform biochemical pharmacology assays. The techniques provided in this Core allow interrogation of receptors associated with drugs of abuse and their signaling. Most researchers who used the Core are either behavioral scientists or chemists. The services provided by the Core are valuable to these investigators, expanded their research and have resulted in many publications. The Core also has provided preliminary data for grant applications and several NIH grants were awarded. The receptors of drugs of abuse that the Core has investigated to date include opioid receptors (MOPR, DOPR, KOPR, NOPR), cannabinoid (CB1 and CB2) receptors, nicotinic cholinergic receptors (nAChRs) and dopamine and sigma receptors. In the requested funding period, the Core will perform the following services: (1) Radioligand binding to the aforementioned receptors related to drug abuse and others when necessary; (2) Assessment of G protein-coupled receptor (GPCR) activation, including cAMP level, [35S]GTP?S binding, p44/42 MAP kinases phosphorylation, ?-arrestin recruitment; (3) Determination of agonist bias for GPCRs using [35S]GTP?S binding or cAMP and ?-arrestin recruitment and CRISPR cell lines; (4) Autoradiography of radioligand binding to opioid and dopamine receptors and (5) Autoradiography of opioid agonist- promoted [35S]GTP?S binding in brain sections; (6) Immunoblotting of MOPR, KOPR and phosphorylated KOPR in cultured cells and in rodent brains; (7) Internalization of MOPR, DOPR and KOPR and CB1 in cultured cells and KOPR in mouse brains; (8) Providing purified antibodies against MOPR, KOPR and phospho-KOPR to researchers; (9) Training of personnel of other laboratories. For the requested grant period, the Core will perform at least 15 collaborative projects with NIH-funded investigators across the country. The innovation lies in the proposed studies, which will address a wide variety of questions related to drug abuse, including elucidation of impact of adolescent and adult chronic exposure to morphine, cocaine or nicotine on MOPR, dopamine and/or nAChR expression and/or signaling in adults and offspring, respectively; search for KOPR agonists that do not cause KOPR phosphorylation (likely G protein-biased); effects of AMP-activated protein kinase (AMPK) deletion on expression of MOPR and nAChR; screening for allosteric modulators of CB1 receptors and determination of how they alter ligand binding; and investigation of agonist biases for CB1 and CB2 receptors by using CRISPR cell lines with either individual G proteins or arrestins deleted. The studies are novel and the Core will augment these research projects beyond the original scope. Thus, the Core will make significant contribution to the area of substance abuse research.